Age-related macular degeneration (AMD) affects the macula and gradually destroys central vision, which is critical to seeing objects clearly and for performing common daily tasks, such as reading and driving. AMD is painless, and, in some cases, the degeneration happens so slowly that patients fail to notice the changes in their vision. However, in other cases, AMD can progress rapidly and lead to a total loss of vision in both eyes.
AMD occurs in two forms:
- Dry AMD is a retinal degenerative disease associated with aging. It usually begins when drusen (tiny yellow or white pieces of fatty protein) accumulate under the retina. Over time, areas of atrophy can form, which may eventually involve the macula and lead to blindness. In Dry AMD, vision loss is usually gradual. People who develop dry macular degeneration must carefully and constantly monitor their central vision. Untreated, Dry AMD can change into the more aggressive form of macular degeneration called wet AMD.
- Wet AMD results from the growth of abnormal blood vessels underneath the retina. Wet AMD is commonly referred to as choroidal neovascularization (CNV), as the vessels originate from the layer under the retina called the choroid. The new blood vessels may leak fluid or blood, blurring or distorting central vision. This condition is likely to result in a more rapid loss of vision than Dry AMD. Left untreated, abnormal vessels can leak or grow, reducing detailed vision. This condition is also likely to compromise both eyes eventually. Early detection and treatment is a key factor for preserving central vision as is constant monitoring of the affected area.